Known micromovement devices for achieving precise positioning include a device for carrying out parallel movement or posture control by giving an impact force larger than a frictional force to a mass to be moved which is under the effect of the frictional force (for example, see Japanese Patent Application Laid-Open No. S60-60582) and a device for moving a mobile body by giving an impact force to the mobile body using a piezoelectric and electrostrictive element (for example, see Japanese Patent Application Laid-Open No. S63-299785).
In the former case, electromagnetic repulsive force is used as means for generating an impact force, and the latter case is a micromovement device using rapid deformation of the piezoelectric element, and they are referred to as so called “impact mechanism”. This impact mechanism has a small and simple structure, and capable of moving in micro-steps. For example, the impact mechanism is used for a precise positioning table, a micro manipulator, and the like.
However, the above conventional micromovement device moves in micro-steps, and therefore, fast movement is difficult with the above conventional micromovement device.
It is known that frictional force between a rolling body and an orbital plane decreases when high-frequency micro-vibration is given (for example, see “Friction reduction effect using ultrasonic vibration and application thereof”, Journal of The Japan Society of Mechanical Engineers, 1997, Vol. 100, No. 946, and Ikuta et al., “Hyper Redundant Active Endoscope for Minimally Invasive Surgery”, Journal of The Robotics Society of Japan, 1998, Vol. 16, No. 4), and a bearing mechanism has been suggested that uses this phenomenon to reduce torque during bearing driving and prevent stick slip vibration (for example, see Japanese Patent Application Laid-Open No. H8-74869 and Japanese Patent Application Laid-Open No. 2005-256954). This kind of bearing mechanism exhibits superior performance in terms of precise positioning with friction reduction effect and exhibits superior performance in terms of setting and stability with friction sliding effect.
However, with the above conventional bearing mechanism, fast movement is difficult due to the friction sliding effect.